1. Field of Invention
The invention concerns a process and apparatus for separating metallic from nonmetallic components.
2. Background Information
For reasons of environmental protection and the avoidance of large waste deposits, as well as for the recovery of materials that would otherwise be lost, the recovery of components of waste materials is desirable. Processes for this purpose are already known for waste materials of the electrical industries, in particular electric cables, and the electronic industry in which the cables, equipment, circuit boards, etc. are mechanically comminuted, i.e., shredded, and then separated into metallic and nonmetallic parts by an air screening process. The principal metal obtained thereby is copper, but other metals, such as platinum, gold, palladium, tin and silver are also contained therein, even though in smaller proportions. The disadvantage of this process is the fact that the waste fraction obtained, i.e., essentially the nonmetallic components such as light and heavy synthetic substances and synthetic plastic wastes and textile fibers, still contain approximately 3-15% by weight of unseparated metal and that, furthermore, all of this waste must be deposited in dumps. In the case of certain cable scrap processors the magnitude of such a dump already amounts to 80,000 to 100,000 t. This represents a significant financial burden. In addition, the materials contained in the waste, i.e., both the synthetics and the aforementioned metallic components, cannot be recovered for recycling purposes. This again represents a considerable financial loss.
From DE P No. 25 55 093, the use of a hydrocyclone is known, which in its bottom course precipitates a metal fraction that is as pure as possible. The mode of operation of the process and the apparatus employed are not described. The same is true of DE-AS No. 22 20 132, which relates only to the precipitation of a sinter (iron oxide) from water, in part by gravity sedimentation and in part by centrifugal separation. DE-OS No. 21 39 350 concerns the processing of cable wastes, wherein this mixture is passed into a drum wash and chemically treated therein. Subsequently, the individual components are separated in keeping with their specific gravities by wet mechanical methods. The drying and screening of light materials (paper or the like) by means of hot air is described in DE-OS No. 28 04 548.